MR imaging of soft-tissue infection.

MR imaging is the ideal technique to display the soft-tissue abnormalities produced by infectious processes. In general these soft-tissue alterations consist of signal intensity changes that reflect the increased water content of the soft tissues induced by the inflammatory reactions. In some cases these changes are nonspecific, but in others, MR imaging can be quite specific and helpful in detecting the presence and extent of the infection, which generally is suspected clinically on the basis of physical and laboratory findings. The MR manifestations of soft-tissue infection, including septic arthritis, tenosynovitis, bursitis, cellulitis, necrotizing fascitis, soft-tissue abscess, infectious myositis, HIV-related infection, lymphadenitis and lymphangitis, and a few unusual parasitic and fungal infections, are reviewed.